食蟹猴纹状体内注射α-突触核蛋白预制原纤维对嗅球病理改变的影响

Effect of intra-striatal injection ofα-Synuclein PFF on pathological changes of olfactory bulb in macaca fascicularis

目的探讨α-突触核蛋白预制原纤维(α-Syn PFF)纹状体注射后能否生成病理性α-突触核蛋白(α-Syn),并从纹状体传播至嗅球,从而引起嗅球中神经元损伤。方法3只健康雌性食蟹猴双侧纹状体注射α-Syn PFF作为实验组,以脑立体定向注射手术,将300μgα-Syn PFF(7 g/L)注射到双侧纹状体的6个位点,即每侧纹状体壳核头部注射60μg,体部注射60μg,尾部注射30μg。另2只健康雌性食蟹猴相同部位注射同等剂量磷酸盐缓冲液(PBS)作为对照组。注射2年后,实验猴行安乐死,取出嗅球经固定和切片,然后经尼氏染色检测组织病理改变,免疫组织化学染色检测磷酸化α-Syn(pS129)、酪氨酸羟化酶(TH)、双皮质素(DCX)的表达情况。结果实验组与对照组比较,嗅球中存在pS129阳性聚集体;实验组TH和DCX阳性神经元数量较对照组均显著减少[TH:(27.00±11.22)个vs.(65.80±36.54)个;DCX:(67.60±17.23)个vs.(88.30±19.89)个]。结论食蟹猴纹状体注射α-Syn PFF产生的病理性α-Syn可从纹状体传播至嗅球造成嗅球神经元损伤,诱导嗅球中多巴胺能神经元丢失,并抑制新生神经元生成。

Objective To investigate whether pathologicalα-Synuclein(α-Syn)can be generated after striatal injection ofα-Syn preformed fibrils(PFF),and then spread from striatum to olfactory bulb,thereby causing neuronal damage in olfactory bulb.Methods Three healthy female macaca fascicularis injected withα-Syn PFF into the bilateral striatum were used as the experimental group.300μgα-Syn PFF(7 g/L)was injected into each side of the striatal putaminal nucleus with 60μg in head,60μg in body and 30μg in tail.The other two healthy female macaca fascicularis were injected with PBS as the control group.Two years after the injection,macaca fascicularis were killed.Pathological changes were detected by Nissl staining,and immunohistochemistry was performed to examine the expression levels of phosphorylatedα-Synuclein(pS129),tyrosine hydroxylase(TH)and doublecortin(DCX)in olfactory bulb.Results Compared to the control group,pS129 positive aggregates were found in olfactory bulb of the experimental group.Besides,the number of TH-positive and DCX-positive neurons were significantly decreased in the experimental group[TH:(27.00±11.22)vs.(65.80±36.54);DCX:(67.60±17.23)vs.(88.30±19.89)].Conclusion Pathologicalα-Syn can spread from striatum to olfactory bulb and induce the loss of dopaminergic neurons,inhibiting the generation of newborn neurons in olfactory bulb of macaca fascicularis.